MythBusters – a tree is 90% air

October 9th, 2008 | Tags: ,

Dear Mythbusters. I hope you know that I think you are awesome. I know you are not scientists, but rather master robot builders. I respect that. I envy your robot-building abilities. Please forgive me for pointing this out – but even if a tree is 90% air, that does not mean a ball has a 90% probability of passing through it.

For those of you who are unaware, in the last episode of MythBusters, they explored the idea that a golf ball should pass through a tree 90% of the time. What if they were to test following alternative myth:

A golf ball has a 90% chance of passing through something that is 90% air.

Here is my test object:

Screenshot 05

It is a steel box with air inside. I did not give the dimensions, but you can imagine it would not be difficult to make this 10% steel and 90% air. What would happen if I hit a golf ball at this? I think there were would be a 0.000000000000000000001% percent chance of it going through (smaller than that – but I think you get the idea).

What is really important is the scattering cross-section, not the density.

  1. October 13th, 2008 at 22:56
    Reply | Quote | #1

    Interesting post !! very well said. found your name in a comment on Bad Astronomy . And checked out your site .

  2. jason
    January 22nd, 2009 at 02:12
    Reply | Quote | #2

    The problem is really 3 dimensions versus 2, right?

    They are viewing the scattered cross section in 3 dimensions, but not accounting for how in a cross sections those points form something that is much more dense.

  3. lol
    November 2nd, 2009 at 15:27
    Reply | Quote | #3

    another thing, when they said it was a 90% chance of a ball passing thu(let’s say it was true)it would not mean that 90 out of 100 balls would have to pass, it would mean EACH ball would have a 90% chance, that means you could have 100 balls pass the tree or 100 balls not passing it, get wat i meen?

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